I'd recommend to try ''scamming'' someone by putting all-in these 500$ on some high-tier knife/skin offer on market and wait for that price mistake for, let's say, a week. It won't hurt anyone btw and can potentially make you big profit.
If you don't want to wait, just buy some m9, dunno.
And last, worst way to spend that bank is to buy keys and try make profit from gambling.

Just look for some amazing karambits priced like this that you really really like or Bayonet Lore maybe - it’s sick.
You just have to look for all the karambits and find one you’d love to have.
First question: which knife I prefer?
Second: which skin I like the most?
2 crucial questions.
Karambits, M9s and expensive butterflies are the most prestige ones.

If you deposited $500, bought $500 worth of skins, sold for $1000, you can still request to refund $500 if it's within 30 days of the deposit.
Will it get refunded? It should, either way you can still request it.